JP4251247B2 - Condensation device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a condensing device that cools the exhaust of a steam turbine with an air-cooled condenser, and more particularly to a condensing device that prevents a decrease in the degree of vacuum of the air-cooled condenser accompanying an increase in outside air temperature.
[0002]
[Prior art]
In a thermal power generation facility that generates power by driving a generator with a steam turbine, the output of the steam turbine is proportional to the difference between the inlet-side steam pressure and the exhaust pressure. Therefore, the exhaust of the steam turbine is usually condensed by a condenser and the pressure is reduced.
Thermal power plants installed near waterfront areas and large rivers can obtain a large amount of cooling water, so many water-cooled condensers are installed. However, air-cooled condensers are used in thermal power plants that are installed in areas where cooling water cannot be obtained abundantly. In this air-cooled condenser, a core is constituted by a large number of tubes through which exhaust flows and a large number of fins fixed to the outer surface thereof, and a fan for sending cooling air to the core is provided. FIG. 2 is a process flow diagram showing a thermal power generation apparatus using a condensing device using a conventional air-cooled condenser. The high-pressure steam generated in the boiler 1 is introduced into the high-pressure turbine 3 through the high-pressure steam pipe 2, and the low-pressure steam discharged therefrom is introduced into the low-pressure turbine 5 through the low-pressure steam pipe 4. Exhaust gas from the low-pressure turbine 5 is introduced into an air-cooled condenser 7 through an exhaust pipe 6, where it is cooled and condensed by outside air, becomes condensed water, and returns to the boiler 1 from the water supply pipe 8 again.
[0003]
[Problems to be solved by the invention]
In general, since the cooling water temperature is stable in a water-cooled condenser, even if the outside air temperature changes due to seasonal changes or weather changes, the cooling capacity is hardly affected. However, since the air-cooled condenser uses the heat exchange effect due to the contact between the radiator pipe and the outside air, the cooling capacity fluctuates due to changes in the outside air temperature, especially in summer when the outside air temperature is high. The phenomenon of a decrease in the degree of vacuum in the condenser occurs. Despite the high demand for power generation in summer, when the degree of vacuum of the air-cooled condenser decreases as described above, the work of expansion of steam in the steam turbine (low-pressure turbine 5 in the example of FIG. 2) decreases. Reduces output. In order to maintain the rated output of the steam turbine, it is necessary to increase the amount of steam from the boiler. In this case, the overall efficiency of the power plant is reduced.
Then, this invention makes it a subject to solve such a problem in the condensing apparatus provided with the air-cooling type condenser.
[0004]
[Means for Solving the Problems]
The invention according to claim 1, which solves the above problem, is a condensing device for cooling the exhaust of a steam turbine with an air-cooled condenser, and the air-cooled condenser from the steam turbine by means of water spray means 9 for spraying the cooling water. 7, the exhaust pipe 6 is cooled.
The invention according to claim 2 is a preferred embodiment of the condensing device according to claim 1, wherein the amount of cooling by the sprinkling means 9 is increased in proportion to the increase in the outside air temperature, or the outside air temperature is increased. Is configured to start cooling by the sprinkling means 9 or to increase the cooling amount when it exceeds a set value.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a process flow diagram showing a thermal power generation apparatus using the condensing apparatus of the present invention, and the same parts as those in FIG. In the present invention, sprinkling means 9 is provided in the exhaust pipe 6 for introducing the exhaust discharged from the low-pressure turbine 5 into the air-cooled condenser 7. The watering means 9 includes a watering nozzle 10 for spraying cooling water on the outer periphery of the exhaust pipe 6 having a predetermined length, a cooling water pipe 11 for supplying cooling water to the watering nozzle 10, a supply pump 12 provided in the cooling water pipe 11, and adjustment. It has a valve 13 and a water tank 14 for storing cooling water. As an example, the exhaust pipe 6 has a diameter of about 1 m60 cm and a total length of about 16 m to 20 m. Therefore, the watering nozzle 10 is preferably installed so that water can be sprayed as uniformly as possible around the entire circumference of the large exhaust pipe 6.
Further, a cooling water recovery facility is provided below the exhaust pipe 6, and the recovered cooling water is cooled by a cooling device such as a relatively small capacity cooling tower and then returned to the water tank 14, whereby the cooling water is circulated and used. You may do it.
[0006]
The control valve 13 is controlled by a temperature controller 16 that outputs a control signal corresponding to a temperature signal from a temperature detector 15 that detects the outside air temperature. That is, when the outside air temperature rises above the set value, the output of the temperature controller 16 increases in proportion thereto, the opening degree of the control valve 13 increases, the cooling amount increases, and conversely the value at which the outside air temperature is set. When the temperature is further lowered, the output of the temperature controller 16 is reduced in proportion thereto, the opening degree of the control valve 13 is reduced, and the cooling amount is reduced.
As another method, a temperature switch that operates when the outside air temperature exceeds a set temperature is provided, and the adjustment valve 13 is opened during the operation to start cooling by the water spraying means 9, or the temperature switch is activated when the temperature switch is operated. It is also possible to adopt a two-stage control method that increases the cooling by the sprinkling means 9 by switching from the opening to the high opening.
[0007]
Instead of using the temperature controller 16 as described above, a vacuum degree controller can also be used. That is, the degree of vacuum in the air-cooled condenser 7 is detected by the vacuum detector, and the degree of vacuum controller is configured to control the adjustment valve 13 so that the detected value becomes a preset degree of vacuum. The same control may be performed by detecting the pressure of the exhaust pipe 6 instead of the degree of vacuum.
As another method, the control valve 13 can be a manually operated valve, and the amount of cooling by the sprinkling means 9 can be changed as needed according to the value of the outside air temperature. Such a configuration is suitable for cases where the outside air temperature fluctuates only relatively slowly, and has the advantage that the apparatus is simple.
[0008]
【The invention's effect】
As described above, the condensing device according to the first aspect is characterized in that the exhaust pipe from the steam turbine to the air-cooled condenser is cooled by the watering means for spraying the cooling water. Accordingly, when the outside air temperature rises and the cooling capacity of the air-cooled condenser decreases, the decrease can be compensated by the cooling action of the watering means. Therefore, even if the outside air temperature rises, the vacuum degree of the air-cooled condenser can be prevented from lowering and the output of the steam turbine can be prevented from lowering. In addition to the cooling effect of water, the latent heat of vaporization when part of the water evaporates can also be used, so that the exhaust can be efficiently cooled with less cooling water.
Furthermore, the cooling water used for the watering means may be very small as compared with the cooling water in the water-cooled condenser, and can be easily installed even in an area where a large amount of cooling water cannot be obtained. Moreover, since the amount of cooling water is small, the cooling water can be circulated and used after cooling with a cooling device such as a cooling tower having a relatively small capacity.
[0009]
The condensing device according to claim 2 increases the amount of cooling by the sprinkling means 9 in proportion to the rise in the outside air temperature, or starts cooling by the sprinkling means 9 when the outside air temperature exceeds a set value. It is configured to increase the cooling amount. Thereby, the degree of vacuum of the air-cooled condenser can be stabilized, and the output fluctuation of the steam turbine can be reduced.
[Brief description of the drawings]
FIG. 1 is a process flow diagram showing a thermal power generation apparatus using a condensing apparatus of the present invention.
FIG. 2 is a process flow diagram showing a thermal power generation apparatus using a condensing device using a conventional air-cooled condenser.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Boiler 2 High pressure steam pipe 3 High pressure turbine 4 Low pressure steam pipe 5 Low pressure turbine 6 Exhaust pipe 7 Air-cooled condenser 8 Water supply pipe 9 Sprinkling means 10 Sprinkling nozzle 11 Cooling water pipe 12 Supply pump 13 Control valve 14 Water tank 15 Temperature detector 16 Temperature controller

Claims (2)

In the condensing device that cools the exhaust of the steam turbine with the air-cooled condenser 7, the exhaust pipe 6 from the steam turbine to the air-cooled condenser 7 is cooled by the sprinkling means 9 that sprays the cooling water. Condensation device characterized by. The amount of cooling by the sprinkling means 9 is increased in proportion to the rise of the outside air temperature, or the cooling by the watering means 9 is started or the amount of cooling is increased when the outside air temperature exceeds a set value. Condensation device as described.

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